Radiochemical Method Research Articles

Controlling the Redox Chemistry of Cobalt Radiopharmaceuticals.

The elementally matched 55Co2+/3+ (t1/2=17.53 h, Iβ+=77 %)/58mCo2+/3+ (t1/2=9.10 h, internal conversion=100 %) radioisotope pair is of interest for development of paired diagnostic/therapeutic radiopharmaceuticals. Due to the accessibility of the nat/55Co2+/3+ redox couple, the redox state can be readily modulated. Here, we show that macroscopic and radiochemical redox reactions can be closely monitored and controlled using spectroscopic and radiochemical methods. We employ model systems to inform how to selectively synthesize thermodynamically favored oxidation state coordination complexes. In addition to exogenous oxidants, our data indicates that 55Co-induced radiolysis of water efficiently and directly drives selective oxidation to the 55Co3+ species under no-carrier added (n.c.a.) conditions. Our synthetic strategies subsequently stabilize the respective 55Co2+ or 55Co3+ species for targeted positron emission tomography imaging in a mouse tumor model.

Comprehensive review of 2[formula omitted] decay half-lives

The double-beta (2β)-decay is the rarest nuclear physics process, and its experimental half-lives (T1/2) exceed the age of the Universe from nine to fourteen orders of magnitude. Double-beta decay was observed, and its half-life was measured in 14 parent nuclei using direct, radiochemical, and geochemical methods. The decay observables are analyzed using the Evaluated Nuclear Structure Data File (ENSDF) procedures, and the recommended T1/2 were deduced. Using the calculated values of phase factors, the effective nuclear matrix elements were extracted and compared with available data. Thousands of theoretical and experimental works have been dedicated to these topics in the last 85 years, and we present two data sets of recommended values to encapsulate the results.

Controlling the Redox Chemistry of Cobalt Radiopharmaceuticals

The elementally matched 55Co (t1/2 = 17.53 h, Iβ+ = 77%)/58mCo (t1/2 = 9.10 h, IC= 100%) radioisotope pair is of interest for development of paired diagnostic/therapeutic radiopharmaceuticals. Due to the accessibility of the Co2+/3+ redox couple, the redox state can be readily modulated. Here, we show that macroscopic and radiochemical redox reactions can be closely monitored and controlled using spectroscopic and radiochemical methods. We employ model systems to inform how to selectively synthesize thermodynamically favored coordination complexes. In addition to exogenous oxidants, our data indicates that 55Co‐induced radiolysis of water efficiently and directly drives selective oxidation to the Co3+ species under no‐carrier added (n.c.a.) conditions. Our synthetic strategies subsequently stabilize the respective 55Co2+ or 55Co3+ species for targeted Co‐compounds’ imaging in a mouse tumor model.

Application and Experimental Substantiation of the Radioecological Model for Prediction in Behavior 90Sr in Cultivated Soil-Crop System: A Case Study of Two Experimental Agricultural Fields.

The radioactive fission product 90Sr has a sufficient half-life (28.8 years) to be detected long after its appearance in the environment. After its uptake into the soil-edible plant system, it enters the food chain and represents a potential source of contamination that threatens human health. Due to these facts, tracking the distribution of the artificial radionuclide 90Sr in the soil-edible plant system is a subject of intense research. The tracking of the 90Sr radionuclide distribution in the soil profile, as well as in the crops on the long-term experimental fields was carried out using beta radiation spectrometry. The radiochemical analytical method was used to analyze the 90Sr content in cultivated soil and crops. The conducted study focused on the experimental substantiation of the developed model for predicting the behavior of 90Sr in the cultivated soil-crop system. The results of using the applied radioecological model for the transfer of 90Sr from the soil to the above-ground part of crops showed a relatively good agreement with the experimentally determined values of the soil-crop transfer factor, which indicates that the used model can be successfully applied for the prediction of the behavior of 90Sr in the soil-soil solution-crop system.

An approach for the indirect determination of 238U and 232Th content in ceramic products based on gross alpha and gross beta measurement

The aim of this work was the development of a procedure for the indirect characterization of 238U and 232Th in ceramic products using the quantification of gross alpha and gross beta activities in a low background proportional counter, which is less time consuming and cheaper than the direct radiochemical methods and gamma spectrometry. The procedure was applied, first, to a reference material used to fine-tune the procedure and statistical techniques, and then, for two types of ceramic products: micronized zircon and zircon flour samples, and spray-dried ceramic powders (atomized).This procedure requires obtaining linear regression models for estimating the activity of 238U and 232Th as a function of specific gross alpha and gross beta measurements. Regression models must be obtained for each type of ceramic material together with the range of application of the model, which depend primarily on the ratio between 238U and 232Th activities. The applications to micronized zircon and zircon flours, and spray-dried ceramic powders demonstrated that the models obtained for the indirect characterization of 238U and 232Th activities explain more than 95% of the variability in the data.In addition, those models were used for predicting the results of new validation samples. Regarding the micronized zircon and zircon flours, predictions were good for the 238U activity with a relative bias of less than 10%, while they were not so accurate for the 232Th activity, with a relative bias of less than 15% for most of the samples. For spray-dried ceramic powders, the predictions were quite good for the 238U activity with a relative bias of less than 20% irrespective of the cluster to which the validation sample belongs, and similarly for the 232Th activity.

Gamma Radiation-Mediated Synthesis of Antimicrobial Polyurethane Foam/Silver Nanoparticles.

Nosocomial infections represent a major threat within healthcare systems worldwide, underscoring the critical need for materials with antimicrobial properties. This study presents the development of polyurethane foam embedded with silver nanoparticles (PUF/AgNPs) using a rapid, eco-friendly, in situ radiochemical synthesis method. The nanocomposites were characterized by UV-vis and FTIR spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray technique (SEM/EDX), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile and compression strengths, antimicrobial activity, and foam toxicity tests. The resulting PUF/AgNPs demonstrated prolonged stability (over 12 months) and good dispersion of AgNPs. Also, the samples presented higher levels of hardness compared to samples without AgNPs (deformation of 1682 µm for V1 vs. 4307 µm for V0, under a 5 N force), tensile and compression strength of 1.80 MPa and 0.34 Mpa, respectively. Importantly, they exhibited potent antimicrobial activity against a broad range of bacteria (including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis) and a fungal mixture (no fungal growth on the sample surface was observed after 28 days of exposure). Furthermore, these materials were non-toxic to human keratinocytes, which kept their specific morphology after 24 h of incubation, highlighting their potential for safe use in biomedical applications. We envision promising applications for PUF/AgNPs in hospital bed mattresses and antimicrobial mats, offering a practical strategy to reduce nosocomial infections and enhance patient safety within healthcare facilities.

Effective dose evaluation for external exposure from surface soil by using resrad-onsite code

An annual effective dose evaluation from Dong Nai surface soil (45 samples) to humans was carried out in this work. ResRad-Onsite software has been applied to estimate the maximum exposure dose by considering different exposure levels across an area of ​​5905.7 km2 with a topsoil thickness of 20 cm. The calculation grid used in ResRad Onsite software is divided in the form of a circle of radius 3, 5, 10, 20, and 30 km, respectively, calculated from the circle center in terms of 16 wind directions. A high-purity germanium detector (HPGe) was used to determine 238U, 232Th, 226Ra, 137Cs, and 40K isotopes. The range activity concentrations of them were found to be 6.46 ÷ 48.11; 13.95 ÷ 58.75; 5.71 ÷ 35.27; 0.15 ÷ 1.23 and 6.7 ÷ 222; mBq/g, respectively. The isotope 239,240Pu was determined by the radiochemical separation method, measured on the alpha spectrometer system, and the calculated value range is 0.009 ÷ 0.073 mBq/g. The activity of 90Sr was determined by separation technique, measured on a low-background alpha/beta total counting system (MPC 9300) with a calculated value range of 0.10 ÷ 0.83 mBq/g. By ResRad-Onsite code, the external effective dose derived from the ground (excluding Radon’s contribution) is calculated to be 170 ÷ 658 µSv/year with an average value is 368.6 µSv/year. The external dose from the soil is 136.5 µSv/year (accounting for 37%). The results showed that the annual radiation dose distribution derived from the ground equivalent to the average of some different regions in the territory of Vietnam and the world. In addition, the external effective dose from the ResRad-Onsite code tended to be about 1.36 times smaller than the practical measured due to the library’s different dose conversion coefficients.

Radiochemical diagnostics at the National Ignition Facility.

Since the National Ignition Facility (NIF) was commissioned in 2009, radiochemical techniques have been viewed as a potential method for diagnosing the performance of an NIF fusion shot. Radiochemical methods can also be used in conjunction with NIF shots to measure nuclear reaction cross sections in regimes that are inaccessible at accelerator facilities and can provide a route to produce radioactive tracer materials that can be used for other applications. This review presents the current status of radiochemical diagnostics at the NIF. Experimental results and the status of both solid and gaseous debris collection radiochemistry are presented.

Development of a radiochemical test procedure for the separation of aerosol-borne allergens

An innovative radiochemical method has been developed to determine the filtration efficiency of HEPA filters for biological nanoparticles. The setup based on EN 1822, for flat sheet media, is up to 40 times more sensitive for a single particle than methods based on particle counting, even for low particle concentrations. To achieve such a high sensitivity the radioactive tracer technique is utilised using a solution of bovine serum albumin (BSA) labelled with radioactive iodine (131I). With the aid of an aerosol generator, this solution is nebulised into nanoparticles of a defined size, which are then passed to the test filter via a compressed air flow. On the raw and clean gas side of the test filter, the 131I is measured with two NaI(Tl) detectors. By balancing the measurement data with each other, the filter efficiency can be determined. Initially, the setup has been validated with current particle counting methods, according to EN 1822, to ensure its functionality. Subsequently, the first experiments with radiolabelled nanoparticles gave promising results, as will be shown below. Further experiments also yielded information about filter clogging and its influence on the filter efficiency.

Accelerator production, radiochemical separation and nanoradiopharmaceutical formulation using 69Ge: A next generation PET probe

Positron emission tomography (PET) has revolutionized the field of molecular imaging of cancer. The driving forces in the latest resurgence of PET are the advances in nano-oncology and availability of newer radioisotopes with attractive nuclear decay characteristics. Germanium-69 (69Ge; T½ = 39 h, 21 % β+, Emax = 1205 keV) is one such radioisotope whose potential is yet to be fully explored for PET imaging. The adequately long half-life of 69Ge, makes it an ideal choice for PET imaging using radiolabeled nanoformulations, which are expected to circulate for a relatively longer time in the biological system. In this study, we report the production of 69Ge via 69Ga (p, n) 69Ge reaction using natural Ga2O3 target. A facile radiochemical separation method based on selective precipitation of Ga at pH ∼7 was developed for isolating no-carrier-added (NCA) 69Ge from the irradiated target in a form suitable for in vivo animal studies. A chelator-free approach was optimized for radiolabeling superparamagnetic arginine grafted iron oxide nanoparticles (AMNPs) with 69Ge for potential use in dual modality PET/magnetic resonance imaging (MRI) and magnetic hyperthermia therapy of cancer. The radiolabeling yield of 69Ge-AMNPs was >95 % and the radiolabeled nanoformulation was stable even after 72 h. As a proof of concept, the suitability of the radiolabeled nanoformulation for in vivo PET imaging was demonstrated in Wistar rats. Overall, this strategy of production, radiochemical separation and radiopharmaceutical formulation might aid towards development of potent agents for cancer theranostics.

Radioecological monitoring of 90Sr and 137Cs accumulation in fish organisms in certain water bodies of the forest-steppe zone of Ukraine

The study aims to determine the radionuclide contamination formation patterns in ichthyofauna representatives of some Forest Steppe of Ukraine water bodies and to establish reference values for the specific activity of 90Sr and 137Cs in the fish body as of 2021. To determine the radionuclide pollution levels in the industrial ichthyofauna representatives in the water areas of the Kaniv Reservoir, the Kosivskyi, the Bila Tserkva Middle, and the Bohuslav Reservoirs on the Ros River and in the unregulated sections of the Ros River (above the city of Bila Tserkva) and Hnyliy Tikych (the village of Stavyshche) as of 2021, the following fish species were selected: red snapper - Rutilus rutilus L., flatfish - Blissa bjoerkna L., common bream - Abramis brama L., silver crucian carp - Сarassius gibelio (Bloch), bream - Alburnus alburnus alburnus L.; pike - Esox lucius L. (peaceful species); pike perch – Stizostedion lucioperca L.; European-Asian river perch – Perca fluviatilis fluviatilis L. (predatory species). The specific activity of 90Sr and 137Cs was determined in the entire fish body by generally accepted radiochemical and gamma spectrometric methods. In 2021, the registered average specific activity of 90Sr in fish of various species of the Kaniv Reservoir ranged from 0.6 to 1.3; 137Cs - from 2.4 to 13.2 Bq/kg. The average specific activity of 90Sr in fish of different species of the Kosiv Reservoir ranged from 0.1 to 0.5, that of 137Cs – from 0.2 to 2.1 Bq/kg, Bila Tserkva Middle ranged, respectively, from 0.2 to 0.8 and from 0.8 to 4.0, Bohuslav – from 0.1 to 0.5 and from 0.5 (bream) to 3.1 Bq/kg. The average content of 90Sr and 137Cs in the body of fish fished in unregulated sections of the Ros and Hnyliy Tikych rivers was 0.1–0.5 and 0.5–2.0 Bq/kg, respectively. The specific activity of 90Sr in peaceful and predatory fish of most of the studied reservoirs probably did not differ, and we can note only the tendency to the formation of higher levels of accumulation of the radionuclide by peaceful species. However, the values of the specific activity of 137Cs of predatory species exceeded the corresponding values that were registered in peaceful fish. The levels of fish radionuclide contamination in all the studied reservoirs, except for the Kaniv Reservoir, did not differ reliably. The increased content of radionuclides in the Kaniv Reservoir fish compared to other reservoirs of the Forest Steppe can be explained by the constant influx of radionuclides from the ecosystem of the Kyiv Reservoir through the Kyiv HPP dam. During the research period, 58–74% of the total activity of peaceful fish in forest-steppe reservoirs was formed by 137Cs, that of predatory species made 82–93%. The research results made it possible to determine reference and screening values in the specific activity of radionuclides in the fish of the forest-steppe reservoirs as of 2021. For peaceful fish, the value of the reference 90Sr activity in the studied reservoirs of the Forest Steppe is 1.0, the screening activity - 3.0, predatory fish - 0.5 and 2.0 Bq/kg, respectively. For 2021, the reference value of the specific activity of 137Cs in the body of peaceful fish of the Kaniv Reservoir makes 3.2, the screening value - 10.0, the Kosiv, Bila Tserkva Middle, Bohuslav reservoirs,the Ros and Hnyliy Tikych rivers are 2.0 and 6.0 Bq/, respectively kg; that of predatory fish of the Kaniv Reservoir - 12 and 36, respectively, Kosiv, Bila Tserkva Middle, Bohuslav Reservoirs, the Ros and Hnyliy Tikych rivers - 3.0 and 10.0 Bq/kg, respectively. Key words: water bodies of the Forest Steppe, fish, radionuclides.

POSSIBILITIES OF NEUTRON ACTIVATION ANALYSIS FOR STUDYING THE CORROSION BEHAVIOR OF METALLIC MATERIALS IN MOLTEN SALTS

For the BREST-OD-300 reactor facility [1, 2], the technology for evaluating mixed nitride uranium-plutonium spent economical fuel is being determined [3–9]. To separate MNUP SNF from fuel claddings made of materials with high radiation resistance – ferritic-martensitic steel EP-823 [10–16], it is planned to use pyrometallurgical grades of “soft chlorination” [17]. When alloying and impurity elements of steel EP-823 are dissolved in molten salts of eutectic composition based on lithium and potassium chlorides, the melt will be contaminated. For the same reason, the formation of volatile compounds will occur, with their further mass transfer from hot to cold sections of process equipment. When studying the corrosion behavior of metals and alloys in liquid media, the problem often arises of determining small amounts of dissolution products in solution. This problem arises, for example, the rate of dissolution of microimpurities. The sensitivity of the usual, traditional methods used in corrosion testing such as mass loss or colorimetric determination of corrosion products in solution is often insufficient to make appropriate measurements. In these cases, the most effective is the use of the radiochemical method of neutron activation analysis based on. qualitative and quantitative determination of chemical elements, based on the measurement of the radiation characteristics of radionuclides formed during the irradiation of materials with neutrons. This paper presents the results of a study of the corrosion behavior and mass transfer of corrosion products of EP-823 steel pre-irradiated in the IVV-2M research nuclear reactor in molten salts 2KCl–3LiCl and 2KCl–3LiCl–PbCl2 at temperatures of 500 and 650°C for 24 h. It is shown that the method of neutron activation analysis can be used to study the corrosion behavior of EP-823 steel in molten salts of various compositions.

Advancing environmental monitoring: A comparative analysis of sequential radiochemical methods for precise alpha-particle spectrometry analysis of 241Am in soil and marine sediment samples

Environmental monitoring of alpha-emitting radionuclides is crucial for assessing the long-term impacts of nuclear activities and understanding ecosystem dynamics. Thus, long-term marine environmental monitoring needs a precise analytical method for determining isotopes in sediment and soil samples. Because 241Am is the first decay product of 241Pu, its activity in the environment will grow during the next 50 years. This study aims to compare and evaluate different sequential radiochemical methods for 241Am analysis, focusing on their precision and accuracy, to establish a more rapid, refined and reliable approach for environmental monitoring. Four radiochemical methods for 241Am determination in soil and marine sediment samples were compared using alpha-particle spectrometry. This sensitive technique plays a key role in quantifying low-level radioactive contaminants in sediment and soil samples. The procedure was optimised using reference materials prepared by IAEA: sediment (IAEA-300, IAEA-384 and IAEA-385) and soil (IAEA-327 and IAEA-375), and digestion, radiochemical separation, and purification on anion exchange resin (AG 1X8) and chromatographic resins (UTEVA, TRU) were used. The effectiveness of the Ca-oxalate precipitation method for iron removal was also evaluated. We used microcoprecipitation on neodymium fluoride (NdF3) to prepare measurement sources. As a significant outcome, we suggested the potential exclusion of co-precipitation (method D) in the determination of the 241Am isotope in sediment and soil samples. This recommendation aligns with our goal of developing a precise sequential radiochemical method for alpha-particle spectrometry. Our approach offers a valuable and optimised tool for monitoring the environmental impact of nuclear activities and accidents, particularly in marine ecosystems.

Some Pathogenetic Aspects of Endocardial Endothelium Damage of Rats as a Result of Stress Effect Complicated by Hypercholesterolemia (original research)

The endothelial dysfunction is a predictor of occurrence for many diseases of cardiovascular system and a key link in their pathogenesis, formation and progression of clinical manifestations. Despite the large number of experimental and clinical researches, separate links of pathogenesis of heart endothelial cell damage under stress and in case of its combination with hypercholesterolemia require the further examination. The aim of the work was to investigate the role of nitric oxide, prostaglandins and antioxidants in the pathogenesis of endocardial endothelium damage (by the content of free fatty acids in it and the number of exfoliated cells) as a result of emotional and pain stress and stress complicated by hypercholesterolemia. An electro-impulse model was used to reproduce the stress. Alimentary hypercholesterolemia was modeled by keeping animals on an atherogenic diet for 2 months. To establish the role of individual pathogenetic links in the mechanisms of endotheliocyte damage, animals were administered the following pharmacological drugs: L-arginine (a substrate for the synthesis of nitric oxide), a prostaglandin synthesis blocker indomethacin, and prostenon (a synthetic analog of prostaglandin E2, which has an antioxidant effect). The state of endocardial endothelium was examined by using the light microscopy, analyzing the smears-imprints from macropreparations of ventricles by counting the number of endothelial cells in them. The content of free fatty acids was determined by the radiochemical method. It was shown that L-arginine significantly limits the damaging effect of the studied pathogenic factors on endocardial endothelium, reducing the number of exfoliated cells. The use of prostenon gives a slight, statistically unreliable positive effect. The use of indomethacin increases the damage of endothelial cells, which indicates the cytoprotective effect of prostaglandins under stress. All three studied preparations have no significant effect on the metabolism of free fatty acids both in case of “pure” emotional and pain stress and under stress complicated by hypercholesterolemia. The hypercholesterolemia of alimentary origin significantly limits the cytoprotective effect of L-arginine and prostenon on endocardial endothelium under stress action. In relation to indomethacin, in this situation, an increase of cell desquamation is observed, which indicates a decrease of prostaglandins protective effect.

The study of gross beta-radioactivity of some medicinal plants in conditions of outdoor hydroponics and soil culture in Ararat Valley

Background: Technogenic and natural radionuclides (RN) along the biogeochemical chains of agrocenoses may enter the human body through irrigation water- soil- plants- agricultural animals, likewise in hydroponic systems through nutrient solution substrate plants, leading to the development of dangerous diseases. Thus, control of herbal raw material’s gross β-radioactivity and obtaining radioactively safe medicinal raw material are priority issues. Since 1996 we have carried out radio monitoring research in the Ararat valley (where the Armenian Nuclear Power Plant (ANPP) is located) in water, soil, and plant systems in zones of the ANPP with a radius of 2-15, 20 (the territory of Ashtarak city), 30 km (Yerevan, territory of Institute of Hydroponics Problems) (IHP), as well as Dilijan Forest Experimental Station (DFES) (the zone of ANPP with 90 km radius). Studies have shown that in natural waters (artesian water, Hrazdan, Qasakh, Metsamor rivers), soils and in various crops (vegetables, fruit of trees, etc.) of Ararat Valley the content of technogenic RN 90Sr (T1/2=28.6 years) and 137Cs (T1/2=30.1 years) did not exceed maximum allowable concentrations (for drinking water MAC 90Sr=5.0 Bq/L, MAC 137Cs=11.0 Bq/L; for vegetables and fruits MAC 90Sr=50 Bq/L, MAC 137Cs=130 Bq/L). Based on these studies, a complex of practical recommendations in this region will give the opportunity of obtaining ecologically pure agricultural products.Objective: Considering that the accumulation of RN in medicinal plants poses a particularly great threat to obtaining radioecologically safe medicinal raw materials, during 2017-2022 we studied the specificities of gross β-radioactivity and accumulation of controlled technogenic RN (90Sr and 137Cs) in medicinal plants under hydroponics and soil conditions in the Ararat valley (the zone of ANPP with 30 km radius). This has a specific practical significance, as it will enable to obtain the most radio-ecologically safe plant material.Methods: Gross β-radioactivity and content of 90Sr and 137Cs of samples (artesian water (irrigation water), nutrient solution, soil layers with depth of 0 - 30 cm and number of medicinal plants) in it were defined with radio-chemical extraction methods through the radiometer UMF-1500 (made in Russia) with low background. 90Sr was determined by the oxalate method with 90Y. RN were determined in dry sediments of waters, nutrient solution, the ash of plants, and soils. The following chemical reagents were used for the analysis: C2H2O4, HNO3, HCl, CH3COOH, CsCl, Y2O3, YCl3, K2SO4, KI, Sr(NO3)2, CeCl3, Ni(NO3)2, SbCl3, K4[Fe(CN)6] 3H2O and others.Results: The radio-chemical studies showed that the gross β-radioactivity of herbs in hydroponics fluctuated between 250 – 740 Bq/kg, and in soil: 140 – 690 Bq/kg. Thus, the medicinal raw material from the medicinal plants cultivated in outdoor hydroponics and soil, is radioecologically safe, since its gross β-radioactivity does not exceed the threshold of 1.0 Bq/g. Medicinal plants grown in hydroponics and soil, with a slight deviation, show the same gross β-radioactivity decreasing pattern as follows: Peucedanum caucasicum (M.Bieb.) K. Koch. > Lycium barbarum > Eleutherococcus senticosus (Rupr. & Maxim.) > Teucrium polium = Humulus lupulus, variety “Crystal” > Echinacea purpurea (L.) Moench > Humulus lupulus, variety “Chinook” > Humulus lupulus, variety “Newport” > Colchicum speciosum Stev. > Moringa oleifera Lam. Our studies have shown that the proportion of 90Sr and 137Cs together in gross β-radioactivity in different medicinal plants fluctuated between 1.0-7.4 % of dry mass in hydroponics and 1.7-10.1 % of dry mass in soil. In the gross β-radioactivity of medicinal plants the share of 90Sr and 137Cs in hydroponics was 1.2-3.0 and 1.3-2.3 times lower than that of soil plants.Conclusion: In artesian waters, gray soils and different medicinal plants grown in hydroponic settings and soil of Ararat Valley the content of controlled technogenic RN (90Sr and 137Cs) did not exceed MAC. Both medicinal raw materials grown in hydroponic settings and soil in Ararat Valley are radioecologically safe.Keywords: technogenic radionuclides, nutrient solution, herbal raw materials, 90Sr, 137Cs

Radionuclide metrology methods and analysis of the Joint Danube Survey 4 sediment samples

This low-level radionuclide metrology research work was carried out within the Joint Danube Survey 4 (JDS4), coordinated in 2018–2020 by the International Commission for the Protection of the Danube River (ICPDR). The gamma-emitting radionuclides of the sediment samples were analysed by low-level gamma-ray spectrometry. The activity concentration of 90Sr was determined by liquid scintillation counting (LSC) after isolating the radio-strontium using a new radiochemical separation method. The results of the radiometric analysis of 90Sr, 137Cs and naturally occurring radionuclides 40K, 210Pb, 226Ra, 228Ra in recent riverbed sediment are presented and discussed focused on public health.

Convenient and Sensitive Measurement of Lactosylceramide Synthase Activity Using Deuterated Glucosylceramide and Mass Spectrometry

Lactosylceramide is necessary for the biosynthesis of almost all classes of glycosphingolipids and plays a relevant role in pathways involved in neuroinflammation. It is synthesized by the action of galactosyltransferases B4GALT5 and B4GALT6, which transfer galactose from UDP-galactose to glucosylceramide. Lactosylceramide synthase activity was classically determined in vitro by a method based on the incorporation of radiolabeled galactose followed by the chromatographic separation and quantitation of the product by liquid scintillation counting. Here, we used deuterated glucosylceramide as the acceptor substrate and quantitated the deuterated lactosylceramide product by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). We compared this method with the classical radiochemical method and found that the reactions have similar requirements and provide comparable results in the presence of high synthase activity. Conversely, when the biological source lacked lactosylceramide synthase activity, as in the case of a crude homogenate of human dermal fibroblasts, the radiochemical method failed, while the other provided a reliable measurement. In addition to being very accurate and sensitive, the proposed use of deuterated glucosylceramide and LC-MS/MS for the detection of lactosylceramide synthase in vitro has the relevant advantage of avoiding the costs and discomforts of managing radiochemicals.

The importance of uranium isotope composition for gross alpha activity regulation

AbstractUranium is a regulated contaminant (maximum contaminant level [MCL] 30 μg/L) that contributes to the gross alpha activity of groundwater. The adjusted gross alpha activity (MCL 15 pCi/L) is determined by subtracting the total uranium activity from the measured gross alpha activity. U.S. water utilities can use mass‐based and radiochemical analysis methods for compliance monitoring of uranium. Mass‐based measurements use a conversion factor of 0.67 pCi/μg of uranium to calculate the adjusted gross alpha activity. This conversion factor assumes that the activity of 234U equals 238U. Here, we present two decades of uranium isotope data measured by alpha spectrometry that shows 234U activity typically exceeds 238U. Using mass‐based measurements, the total uranium activity is biased low causing artificial exceedances of the adjusted gross alpha activity. Therefore, water utilities with gross alpha activities >15 pCi/L should utilize radiochemical analyses for uranium for the most accurate calculation of adjusted gross alpha activity.

Analytical control of the content of radionuclides in feed

The authors determined the radionuclides Cs-137 and Sr-90 in the soils and feeds of the Khvastovichi and Maloyaroslavetsky districts of the Kaluga region, using the radiochemical method. Sample preparation and concentration of the analyzed samples was carried out by the method of "dry salting". It was found that in the studied soil and feed samples, the content of Ss-137 and Sr-90 does not exceed their maximum permissible concentrations.

Correction: Preliminary development of a radiochemical separation method to determine 135Cs and 135Cs/137Cs isotopic ratio by a non-radiometric technique

Correction: Preliminary development of a radiochemical separation method to determine 135Cs and 135Cs/137Cs isotopic ratio by a non-radiometric technique